The present invention deals broadly with the field of windows, and more particularly with those windows, such as double-hung windows, wherein a sash slides within a frame. The invention specifically relates to mechanisms for retaining a window sash within a frame at an intended location along an axis perpendicular to a plane defined by the window frame within which the sash slides, and more particularly to an actuator for such a sash retention mechanism.
The prior art includes many types of windows which are employed to bring light into a building. One popular type of window known in the prior art is a double-hung window, and the background of the present invention will be described in that context (although it should be noted that the present invention can certainly be used with any tiltably removable sliding sash window and is not limited to double-hung windows).
A double-hung window typically employs two movable sash assemblies, each carrying its own pane of glass, which are typically movable vertically within the frame. For most double-hung windows it is highly desirable that the sashes be inwardly tiltable and/or removable, so that the glass portions of the sash assemblies can be easily cleaned. Various types of sash retention mechanisms have been utilized to effect maintenance of a sash in the desired position yet allow it to be tilted inwardly or removed for cleaning. The present invention is directed to a sash retention mechanism actuator, so the remainder to this background discussion will focus on such mechanisms.
One type of sash retention mechanism utilizes a pair of independently-operable latch elements carried by the sash. The latch elements extend laterally out of the sash and into a groove or track formed by the frame. One latch element extends laterally from one side of the sash, and a second latch element extends laterally from the other side of the sash. When it is desired to remove a sash, the person removing the sash releases (i.e., retracts the latch element back into the sash) one latch with one hand and releases the other latch with the other hand. The sash is then tilted or slid out of its normal position and removed from the frame for cleaning. Such an xe2x80x9cindependent-latchxe2x80x9d sash retention mechanism has a number of drawbacks, not the least of which is that the person removing the window sash needs full availability of both hands to effect release of the latches.
To address problems associated with xe2x80x9cindependent-latchxe2x80x9d sash retention mechanisms, attempts have been made to design a mechanism for concurrently releasing both latches (that is, for simultaneously effecting retraction of the latches). One such xe2x80x9cconcurrent-latchxe2x80x9d sash retention mechanism is disclosed in commonly-assigned U.S. patent application Ser. No. 09/328,085, now U.S. Pat. No. 6,141,913. Latch elements (i.e., the elements that extend into the groove or track in the window frame) for xe2x80x9cconcurrent-latchxe2x80x9d mechanisms can move in and out relative to the sash along a straight line or they can pivot in some fashion (as disclosed in the aforementioned commonly-assigned patent application), but regardless of the specific type of latch element being used, an actuator of some sort is necessary to draw the latch element out of the corresponding groove or track in the window frame so that the sash can be removed or tilted as necessary. The present invention relates in particular to an improved actuator for a xe2x80x9cconcurrent-latchxe2x80x9d sash retention mechanism.
While xe2x80x9cconcurrent-latchxe2x80x9d sash retention mechanisms are theoretically superior to xe2x80x9cindependent-latchxe2x80x9d mechanisms due to the one-hand versus two-hand operation advantage discussed above, the actuators in prior art xe2x80x9cconcurrent-latchxe2x80x9d mechanisms have been problematical. For example, one design, shown somewhat pictorially in FIGS. 1-4 hereof, uses a plastic strap captured by a winder to actuate a pair of linear latch elements (not shown).
In the xe2x80x9cplastic-strap/linear-latchxe2x80x9d design discussed immediately above and partially shown pictorially in FIGS. 1-4 hereof, the tilt actuator includes a tilt lever (not shown) mounted at the top of the sash (assuming for the purposes of this discussion that the double-hung window is in its typical, vertical orientation with the sashes sliding up and down rather than side to side). The tilt lever is connected to the upper end of a cylindrical winder which rotates about a vertical axis. The lower end of the winder fits into a round aperture formed by a housing contained within the sash frame.
In addition to the winder aperture, the housing also forms a pair of laterally extending channels that extend from the winder aperture to the outer lateral edges of the housing. The lower end of the winder, the end that rotates within the winder aperture, is slotted in a manner that would appear to be a screwdriver slot as viewed from the bottom. This slot is a simple, vertical-walled slot extending diametrally through the lower end of the cylindrical winder.
A plastic strap, of the type used to bind or bundle various materials, having a generally rectangular cross section, is received within the xe2x80x9cscrewdriver slotxe2x80x9d in the lower end of the winder. Note that FIGS. 2-4 show only the edge of the strap, not its width. When the tilt lever is in its un-activated position the winder slot is aligned with the channels in the housing, as shown in FIG. 2. As the tilt lever is rotated, as shown in FIG. 3, the winder is supposed to evenly and equally act on the strap to simultaneously draw the linear latch elements inwardly and out of their corresponding grooves or tracks in the window frame, to permit tilting/removal of the sash.
While the strap-type actuator mechanism shown in FIGS. 1-4 is an advance over typical xe2x80x9cindependent-latchxe2x80x9d mechanisms that require two-hand operation, it has certain limitations. One of its limitations is that it employs a housing, and another has to do with its use of a strap.
As noted above, one shortcoming of prior art strap-type sash retention mechanism actuators is that they include a xe2x80x9chousing,xe2x80x9d defined herein as a component that receives the lower end of a winder and forms channels for laterally guiding the strap. An actuator housing such as that employed by prior art strap-type actuators is an unnecessary part (as compared to preferred embodiments of the present invention) that adds cost in and of itself, increases the assembly time and cost, and introduces an additional source of friction and binding for the strap, thus potentially making it more difficult to actuate the tilt mechanism.
While the housing of the prior art strap-type actuator design may cause certain problems, FIG. 4 shows what would happen if the housing in this particular design were omitted. Initially, when the tilt lever is in its normal, unactivated position, the slot in the lower end of the winder is aligned with the linear latch elements. See FIG. 2. If the housing were absent, movement of the tilt lever would cause the linear latches to move inwardly only minimally for a given incremental rotation of the winder. Most of this initial movement would be taken up with simply changing the orientation of the strap from straight (FIG. 2) to angled or tangential (FIG. 4). That is, initial movement of the tilt lever would tend to cause the strap to xe2x80x9ctake a tangential shortcutxe2x80x9d and not result in linear movement of the strap in the sense of X degrees of rotation of the winder consistently resulting in Y inches of movement of the strap. Rather, the translation of winder rotation to latch movement would be quite non-linear, and this could be misleading or feel strange to the operator, who might only operate the tilt latch on rare occasion. The rationale for the housing, given the initial, unactivated orientation of the strap slot, can now be understood.
Another shortcoming of this type of actuator mechanism is that the housing can introduce additional friction on the strap, and this can result in binding of the mechanism and possibly strap breakage, over time.
Still another shortcoming of the strap type of xe2x80x9cconcurrent-latchxe2x80x9d actuator discussed above is the strap itself, given that it can become twisted and bind at various locations within the sash, irrespective of whether a xe2x80x9chousingxe2x80x9d is employed.
It is to these dictates and shortcomings of the prior art that the present invention is directed. It is an actuator for a xe2x80x9cconcurrent-latchxe2x80x9d sash retention mechanism which addresses these dictates and problems and provides solutions which make the invention a significant advance over prior art sash retention mechanism actuators of the xe2x80x9cconcurrent-latchxe2x80x9d variety.
The present invention is an actuator device for unlatching a sash tilt latch which is intended to maintain a window sash, such as in a double-hung window, in an intended path of reciprocation during opening and closing of the window. At the same time, however, the latch can be retracted to release the sash from its position in the defined path and allow it to be tilted for cleaning or removal. In a preferred embodiment, a pair of latches which extend oppositely in lateral directions are actuated by the structure. The actuator includes a housing which is mounted to the sash. A winder is rotatably connected to the housing and extends into an interior cavity within the sash. The winder has a longitudinal axis and forms a diametral slot. A flexible cord having a substantially round. cross-section is slidably received within the winder slot. Ends of the cord are connected to the latches. As the winder is rotated in a particular direction, the cord coils around the winder to draw the latches inwardly. The sash is, thereby, released from the frame.
In a preferred embodiment of the invention, the winder includes a slit at its lower end, the slit extending through an imaginary vertical axis about which the winder rotates.
The flexible cord is received within the slit, and, in a preferred embodiment, the cord has a larger diameter than does at least a portion of the slit. A bulge in the slit above its narrowest portion does, however, have a diameter greater than that of the cord. Consequently, prongs defined on opposite sides of the slit can be urged apart to admit the cord into the bulge. With the cord received in the bulge, because of the bulge""s greater diameter than that of the cord, the cord will be free to move through the bulge portion of the slit and will effectively equalize pressure applied to the oppositely facing tilt latches.
The present invention is thus improved apparatus to be employed in mounting and maintaining a sash within a window frame. More specific features and advantages obtained in view of those features will become apparent with reference to the accompanying drawing figures, the DETAILED DESCRIPTION OF THE INVENTION, and appended claims.